AU672296B2 - A method and a device for protecting a printed board against overcurrents - Google Patents

A method and a device for protecting a printed board against overcurrents Download PDF

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Publication number
AU672296B2
AU672296B2 AU63357/94A AU6335794A AU672296B2 AU 672296 B2 AU672296 B2 AU 672296B2 AU 63357/94 A AU63357/94 A AU 63357/94A AU 6335794 A AU6335794 A AU 6335794A AU 672296 B2 AU672296 B2 AU 672296B2
Authority
AU
Australia
Prior art keywords
fuse
printed board
conductor
well
thickness
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
AU63357/94A
Other versions
AU6335794A (en
Inventor
Stefan Lof
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Telefonaktiebolaget LM Ericsson AB
Original Assignee
Telefonaktiebolaget LM Ericsson AB
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Telefonaktiebolaget LM Ericsson AB filed Critical Telefonaktiebolaget LM Ericsson AB
Publication of AU6335794A publication Critical patent/AU6335794A/en
Application granted granted Critical
Publication of AU672296B2 publication Critical patent/AU672296B2/en
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K1/00—Printed circuits
    • H05K1/02—Details
    • H05K1/0286—Programmable, customizable or modifiable circuits
    • H05K1/0293—Individual printed conductors which are adapted for modification, e.g. fusable or breakable conductors, printed switches
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H69/00—Apparatus or processes for the manufacture of emergency protective devices
    • H01H69/02—Manufacture of fuses
    • H01H69/022—Manufacture of fuses of printed circuit fuses
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H85/00—Protective devices in which the current flows through a part of fusible material and this current is interrupted by displacement of the fusible material when this current becomes excessive
    • H01H85/02—Details
    • H01H85/04—Fuses, i.e. expendable parts of the protective device, e.g. cartridges
    • H01H85/041—Fuses, i.e. expendable parts of the protective device, e.g. cartridges characterised by the type
    • H01H85/046—Fuses formed as printed circuits
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K1/00—Printed circuits
    • H05K1/02—Details
    • H05K1/0201—Thermal arrangements, e.g. for cooling, heating or preventing overheating
    • H05K1/0203—Cooling of mounted components
    • H05K1/0209—External configuration of printed circuit board adapted for heat dissipation, e.g. lay-out of conductors, coatings
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K1/00—Printed circuits
    • H05K1/16—Printed circuits incorporating printed electric components, e.g. printed resistor, capacitor, inductor
    • H05K1/167—Printed circuits incorporating printed electric components, e.g. printed resistor, capacitor, inductor incorporating printed resistors
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2201/00—Indexing scheme relating to printed circuits covered by H05K1/00
    • H05K2201/03—Conductive materials
    • H05K2201/0332—Structure of the conductor
    • H05K2201/0335—Layered conductors or foils
    • H05K2201/0347—Overplating, e.g. for reinforcing conductors or bumps; Plating over filled vias
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2201/00—Indexing scheme relating to printed circuits covered by H05K1/00
    • H05K2201/09—Shape and layout
    • H05K2201/09209—Shape and layout details of conductors
    • H05K2201/09654—Shape and layout details of conductors covering at least two types of conductors provided for in H05K2201/09218 - H05K2201/095
    • H05K2201/09727—Varying width along a single conductor; Conductors or pads having different widths
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2201/00—Indexing scheme relating to printed circuits covered by H05K1/00
    • H05K2201/09—Shape and layout
    • H05K2201/09209—Shape and layout details of conductors
    • H05K2201/09654—Shape and layout details of conductors covering at least two types of conductors provided for in H05K2201/09218 - H05K2201/095
    • H05K2201/09781—Dummy conductors, i.e. not used for normal transport of current; Dummy electrodes of components
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2201/00—Indexing scheme relating to printed circuits covered by H05K1/00
    • H05K2201/10—Details of components or other objects attached to or integrated in a printed circuit board
    • H05K2201/10007—Types of components
    • H05K2201/10181—Fuse
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00—Metal working
    • Y10T29/49—Method of mechanical manufacture
    • Y10T29/49002—Electrical device making
    • Y10T29/49107—Fuse making

Landscapes

  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Manufacturing & Machinery (AREA)
  • Fuses (AREA)
  • Emergency Protection Circuit Devices (AREA)
  • Selective Calling Equipment (AREA)
  • Parts Printed On Printed Circuit Boards (AREA)

Abstract

In order to reduce the costs of assembled printed circuit boards, a printed board fuse (1) has been developed, which functions with great reliability at low manufacturing costs. By coating a large area of a printed board with metal, for example, by plating, a well-defined thickness of a metal layer (9) may be achieved in which a fuse (3) has been separated. The well-defined thickness also allows well-defined geometry of the fuse cross-sectional area and fuse length to be achieved and therefore its resistance and interruption characteristics will also be very accurately defined. In case of a temperature rise, the metal layer (9) surrounding the fuse (3) will have a heat dissipating effect on the fuse, implying an essentially reduced risk of board fire. <IMAGE>

Description

1 dh_~_ I/UU/U11 2/5/91 Regulation 3.2(2)
AUSTRALIA
Patents Act 1990
ORIGINAL
COMPLETE SPECIFICATION STANDARD PATENT Application Number: Lodged: e a 0 0 *oo* Invention Title: A METHOD AND A DEVICE FOR PROTECTING A PRINTED BOARD AGAINST OVERCURRENTS
D
s The following statement is a full description of this invention, including the best method of performing it known to us
DESCRIPTION
Technical field The present invention relates to a method and a device for protecting a printed board against overcurrents by mounting thereon a printed board fuse which will interrupt the current in case of overcurrents.
Prior art From, for example, EP-Al 0 270 954 there is previously known a chip-type fuse which may be used mounted on and connected to a printed circuit board/printed board. Said chip-type fuse comprises an insulating member, such as an insulating substrate having a pair of metallic electrodes of 15 thin-film type disposed thereon, between which a current sensitive conductor is connected. Should an overcurrent pass through the fuse, the conductor will melt and the current will be interrupted. In order to prevent, in case of the conductor melting because of an overcurrent, a generated metal vapour from being set free and spreading and also to prevent arc discharge, the conductor is coated with a protective silicone resin film. Despite the small size of the fuse, the insulating member/substrate permits high current intensities. For increased sensitivity, the chip-type fuse may optionally be provided with trimmed portions which would more easily melt in case of an overcurrent.
From FR-A 2 053 881 there is previously known a similar fuse for printed circuits/printed boards. It is made according to the technique for printed circuits or rather by means of a method for analogue circuits such as metal coating, electroplating or attachment of a metallic film.
The fuse is characterized in that the conductive current sensitive circuit contains a plurality of spaced apart constricted areas adjacent extended conductive surfaces. In the case of a temperature rise in the constricted areas, the substrate will not be affected since the constricted areas are located adjacent the extended conductive surfaces, which are exposed to the air so that the heat may be dissipated.
Summary of the invention In order to reduce the costs of printed board assemblies, a printed board fuse has been developed which functions with great reliability at very low manufacturing costs. By coating a large area of a printed board with metal, for example electrolytically, a well-defined thickness of a metal layer may be achieved in which a fuse of, for example, square-wave type has been separated. The welldefined thickness also allows a well-defined geometry of the printed board fuse to be achieved. A prerequisite for a well functioning fuse, which works in a similar way on boards with different layouts, is that the cross-seztional area and length of the printed board fuse and therefore its resistance are very accurately defined. This is achieved by the metal layer surrounding the fuse and in case of a temperature rise said surrounding metal layer will have a heat S" 20dissipating effect on the fuse, implying an essentially reduced risk of board fire.
Description of the drawings Fig. 1 shows a printed board having printed board fuses according to the invention, 25 Fig. 2A shows a printed board fuse with copper plane according to the invention, on an enlarged scale, and Fig. 2B shows a portion of the printed board fuse according to the invention, with indicated measures.
Description of an embodiment For boards containing a large number of components, pattern plating is the most widely used manufacturing method. It is based on the principle of additively building up a pattern, in contrast to the tenting method in whic a pattern is formed by etching. The pattern plating method has its limitations as regards thickness distribution. A variation is often due to the pattern distribution of the layout. Depending on the pattern distribution, the current from rectifiers in a plating bath will be distributed over the surface not protected by photoresist. Insulated conductors without surrounding copper will have a higher current density (A/dm 2 than a conductor located in an area with a large quantity of copper. The current density will determine the rate of precipitation of copper, and the time will determine the thickness. If there is no balanced shape, there may be great differences between different parts of a 1 0 board. By applying the present plating method on the layout according to the invention there wi'l be very small variations in the thickness of the copper plating and it is possible to achieve a very well defined thickness of individual elements.
1 5 By using, for instance, a plating method on a printed board, a fuse of copper may be provided as a conduc- .o tor with very well defined shape and cross-sectional area, and a surrounding area with a uniform and well defined coated copper layer may be achieved. Since the fuse and the surrounding copper layer are made to cover a relatively large area with almost homogenous copper on the printed board, said method makes it possible to predetermine a certain thickness of the copper layer and therefore of the fuse, implying known interruption characteristics. The difference in thickness of one and the same conductor in a fuse with or without surrounding copper plane may amount to as much as 50% depending on the layout of the board, which would essentially alter the interruption characteristics.
Fig. 1 shows a plurality of printed board fuses disposed in a row along one longitudinal side of a printed board 2. Fig. 2 shows a possible configuration of a printed board fuse 1 on said board. Measurements for circuits of this kind are indicated as follows: 1 mil 0,0254 mm, and 1 M 2,54 mm. The individual conductor 3 of the fuse 1 is shaped like a square wave and could be described as a "snake". The length 4 of the fuse or "snake" could be 4 M, where the length of each edge portion 5 is 1 M and the 4 distance 6 between the edges is .1 M. The width 7 of a surrounding copper plane could be 3 M. The width of the conductor 3 to and from the fuse is, for example, 8 mils, while the width of a shorter portion of the fuse, a section 8, is 6 mils in order to provide a defined interruption point for an overcurrent. The distance between the copper plane 9 and the conductor of the fuse could be 8 mils. The thickness of the fuse could be 40 pm, which is obtainable by said shape and method.
While only one shape of the fuse has been described, other shapes of the invention are feasible, in which a well-defined thickness of the conductor and a separate copper plane surrounding the conductor is achievable.
The printed board is typically coated with a lacquer layer.
In order for the fuse to have an increased heat dissipating capacity, the fuse may optionally be provided with an underlying insulated metallic plane of, for example, copper.
*o

Claims (5)

1. A method for manufacturing a printed board fuse to protect a printed board against overcurrents, characterised in that a metal layer is coated on an area of a printed board in which at least one conductor is individually separated, whereby a well-defined thickness of the conductor and of a heat dissipating metal surface separated from and surrounding the conductor is provided.
2. A method according to claim 1, characterised in that a copper layer is deposited by plating in which at least one conductor is individually separated, whereby a well-defined thickness of the conductor and of a heat dissipating copper surface separated from and surrounding the conductor is provided.
3. A printed board fuse for protecting a printed board against overcurrents, characterised in that the fuse consists of a metallic conductor of well-defined shape and thickness, which conductor is separated from a coated metal layer and separately surrounded by a metal surface formed by the metal layer and that the fuse is placed along on the printed board or that a plurality of fuses are placed thereon.
4. A printed board fuse according to claim 3, characterised in that the fuse provided by plating consists of a conductor of copper of well-defined shape and thickness from a coated copper layer and separately surrounded by a eo: copper surface formed by the copper layer and that the fuse is placed alone on the printed board or that a plurality of fuses are placed thereon. o
5. A printed board fuse according to claim 3 or 4, characterised in that the fuse is of square-wave shape and has a section of reduced width. DATED this 24th day of July 1996. TELEFONAKTIEBOLAGET L M ERICSSON WATERMARK PATENT TRADEMARK ATTORNEYS LEVEL 4, AMORY GARDENS 2 CAVILL AVENUE ASHFIELD NSW 2131 AUSTRALIA R, LJD:GL DOC15 AU6335794.WPC ABSTRACT In order to reduce the costs of assembled printed circuit boards, a printed board fuse has been developed, which functions with great reliability at low manufacturing costs. By coating a large area of a printed board with metal, for example, by plating, a well-defined thickness of a metal layer may be achieved in which a fuse has been separated. The well-defined thickness also allows well- defined geometry of the fuse cross-sectional area and fuse length to be achieved and therefore its resistance and interruption characteristics will also be very accurately defined. In case of a temperature rise, the metal layer (9) surrounding the fuse will have a heat dissipating effect on the fuse, implying an essentially reduced risk of board fire. (Fig. 2A) o- *o*°o *o o o** o a *oo
AU63357/94A 1993-05-28 1994-05-26 A method and a device for protecting a printed board against overcurrents Ceased AU672296B2 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE9301825 1993-05-28
SE9301825A SE505448C2 (en) 1993-05-28 1993-05-28 Procedure for manufacturing a circuit board fuse and circuit board fuse

Publications (2)

Publication Number Publication Date
AU6335794A AU6335794A (en) 1994-12-01
AU672296B2 true AU672296B2 (en) 1996-09-26

Family

ID=20390084

Family Applications (1)

Application Number Title Priority Date Filing Date
AU63357/94A Ceased AU672296B2 (en) 1993-05-28 1994-05-26 A method and a device for protecting a printed board against overcurrents

Country Status (10)

Country Link
US (1) US5543774A (en)
EP (1) EP0626714B1 (en)
AT (1) ATE150901T1 (en)
AU (1) AU672296B2 (en)
DE (1) DE69402247T2 (en)
DK (1) DK0626714T3 (en)
ES (1) ES2102798T3 (en)
FI (1) FI942492A (en)
NO (1) NO306036B1 (en)
SE (1) SE505448C2 (en)

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US5914648A (en) * 1995-03-07 1999-06-22 Caddock Electronics, Inc. Fault current fusing resistor and method
US5760674A (en) * 1995-11-28 1998-06-02 International Business Machines Corporation Fusible links with improved interconnect structure
US5699032A (en) * 1996-06-07 1997-12-16 Littelfuse, Inc. Surface-mount fuse having a substrate with surfaces and a metal strip attached to the substrate using layer of adhesive material
US5977860A (en) * 1996-06-07 1999-11-02 Littelfuse, Inc. Surface-mount fuse and the manufacture thereof
US5923239A (en) * 1997-12-02 1999-07-13 Littelfuse, Inc. Printed circuit board assembly having an integrated fusible link
JP3812865B2 (en) * 1998-09-21 2006-08-23 矢崎総業株式会社 Electrical circuit safety device
US6456186B1 (en) * 1999-10-27 2002-09-24 Motorola, Inc. Multi-terminal fuse device
GB0001573D0 (en) * 2000-01-24 2000-03-15 Welwyn Components Ltd Printed circuit board with fuse
US20030048620A1 (en) * 2000-03-14 2003-03-13 Kohshi Nishimura Printed-circuit board with fuse
DE10143277A1 (en) * 2001-09-04 2003-06-26 Siemens Ag Protection circuit for communication devices
US7385475B2 (en) * 2002-01-10 2008-06-10 Cooper Technologies Company Low resistance polymer matrix fuse apparatus and method
JP3952271B2 (en) * 2002-01-31 2007-08-01 富士通株式会社 Semiconductor device and manufacturing method thereof
GB0307306D0 (en) * 2003-03-29 2003-05-07 Goodrich Control Sys Ltd Fuse arrangement
PL360332A1 (en) * 2003-05-26 2004-11-29 Abb Sp.Z O.O. High voltage high breaking capacity thin-layer fusible cut-out
EP1678988A1 (en) * 2003-10-17 2006-07-12 Koninklijke Philips Electronics N.V. Printed circuit board including a fuse
US7477130B2 (en) * 2005-01-28 2009-01-13 Littelfuse, Inc. Dual fuse link thin film fuse
TW200929310A (en) * 2007-12-21 2009-07-01 Chun-Chang Yen Surface Mounted Technology type thin film fuse structure and the manufacturing method thereof
US8525633B2 (en) * 2008-04-21 2013-09-03 Littelfuse, Inc. Fusible substrate
PL2408277T3 (en) * 2010-07-16 2016-08-31 Schurter Ag Fuse element
DE102010063832B4 (en) * 2010-12-22 2020-08-13 Tridonic Gmbh & Co Kg Circuit protection, circuit board and operating circuit for lamps with the circuit protection
US10064266B2 (en) * 2011-07-19 2018-08-28 Whirlpool Corporation Circuit board having arc tracking protection
US9673012B2 (en) * 2012-05-16 2017-06-06 Littelfuse, Inc. Low-current fuse stamping method
JP2017204525A (en) * 2016-05-10 2017-11-16 住友電工プリントサーキット株式会社 Flexible printed wiring board and electronic parts

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US4379318A (en) * 1979-09-21 1983-04-05 Nissan Motor Company, Limited Overcurrent safety construction for a printed circuit board
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Also Published As

Publication number Publication date
NO941963L (en) 1994-11-29
NO306036B1 (en) 1999-09-06
US5543774A (en) 1996-08-06
DK0626714T3 (en) 1997-10-13
FI942492A (en) 1994-11-29
AU6335794A (en) 1994-12-01
FI942492A0 (en) 1994-05-27
DE69402247T2 (en) 1997-07-10
SE9301825D0 (en) 1993-05-28
SE505448C2 (en) 1997-09-01
ATE150901T1 (en) 1997-04-15
DE69402247D1 (en) 1997-04-30
ES2102798T3 (en) 1997-08-01
EP0626714A1 (en) 1994-11-30
NO941963D0 (en) 1994-05-26
SE9301825L (en) 1994-11-29
EP0626714B1 (en) 1997-03-26

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